Some considerations before the clinical application of the novel anatomical plate for oblique lumbar interbody fusion
We sincerely thank Dr. Pu and his colleagues for their interest and constructive comments on our article. In that paper, novel and safe anatomical lateral plates (ALP) with an anatomical design based on the parameters acquired in our previous studies were developed (1,2). The initial design was introduced and its biomechanical performance was verified with the comparison of various internal fixations. Dr. Pu and his colleagues came up with valuable and inspiring advice with regard to further clinical application of ALP. We are glad to have received the comments and would like to take this opportunity to respond and further discuss on the issue.
Regarding the first comment, the length of the ALP was indeed an issue to be resolved for the future clinical application of the plates. However, manufacturing of cortical screw holes with satisfactory safety and accuracy might be difficult due to the limited surgical field. Designing ALP of different sizes is a simple and reasonable solution. Further, in the original design, the length of the plate was planned to be made adjustable. This might be a better option in dealing with the issue and our team is currently working on realizing the idea.
As for the second and third comments, in the study, we attempted to make the anatomical design fit the anterior-lateral side of the vertebral body. In the initial model introduced in this paper, the sagittal arc was 6° for the L2–3 plate and 15° for the L4–5 plate. A coronal curvature of 0.6 cm−1 was acquired based on our previous study. As Dr. Pu et al. pointed out, the endplate fracture would be a concern during the application of ALP. On the one hand, applying the ALP could help decrease the risk of cage subsidence as the construction could be contributive to the stress distribution. But on the other hand, if the endplate is injured during the procedure, which has been reported in previous literature, the risk of relevant complications would increase (3). This is why some surgeons opt not to use lateral platting anymore. Applying ALP could theoretically increase the whole immediate stability of oblique lumbar interbody fusion (OLIF) and decrease the risk of cage subsidence but the rigid construction would also increase the risk of endplate or vertebral fracture, especially in cases with poor bone density. Thus, this is a trade-off between the stability and risk of failure with regard to the individual condition of each patient. Therefore, in our method we applied more screws compared with conventional lateral plates to distribute the stress of the implant-bone interfaces. Strategies to improve the efficacy of using the ALP include: (I) proper intraoperative fluoroscopy to avoid injury to the endplates but this would increase the radiation exposure; (II) further exploration on the screw direction with the use of unlocking screw or semi-locking screw design for a more flexible construction.
The fixation option of OLIF for patients with osteoporosis requires further discussion. For osteoporosis patients, according to current literature, the cage subsidence rate is higher if only the stand-alone technique is applied (4,5). If the bone quality is identified as osteoporosis, surgeons should think carefully whether to perform the OLIF surgery, and stand-alone OLIF in particular. Proper preoperative assessment should be done and whether the patient is indicated for OLIF is a primary issue to consider.
In short, as stated in the paper, this is the first verification step for the ALP concept and the design was based on our previously acquired anatomical parameters. For clinical application, subsequent research is required and we are currently endeavoring with different trials and errors. Thank you again for the kind suggestions and we appreciate the communication.
Acknowledgments
Funding: This work was supported by grants from No.2021-NCRC-CXJJ-ZH-18 of Clinical Application-oriented Medical Innovation Foundation from National Clinical Research Center for Orthopedics, Sports Medicine & Rehabilitation and Jiangsu China—Israel Industrial Technical Research Institute Foundation.
Footnote
Provenance and Peer Review: This article was commissioned by the editorial office, Annals of Translational Medicine. The article did not undergo external peer review.
Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://atm.amegroups.com/article/view/10.21037/atm-2022-72/coif). All authors report that the design of the anatomical plates used in the study has received a utility model patent in China (No. ZL202121374755.X). HW also reports that this work was supported by grants from the No. 2021-NCRC-CXJJ-ZH-18 of Clinical Application-oriented Medical Innovation Foundation from National Clinical Research Center for Orthopedics, Sports Medicine & Rehabilitation and Jiangsu China—Israel Industrial Technical Research Institute Foundation. The authors have no other conflicts of interest to declare.
Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.
Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.
References
- Huang W, Zhou P, Xie L, et al. The trajectory characteristics and clinical significance of the left-sided lumbar segmental artery: a prospective cross-sectional radio-anatomical study. Quant Imaging Med Surg 2022;12:1977-87. [Crossref] [PubMed]
- Huang W, Wang H, Zhou P, et al. Analysis of the Curvature and Morphologic Features of the Lumbar Vertebral Endplates Through the Transverse Section: A Radioanatomical Study. World Neurosurg 2021;150:e500-10. [Crossref] [PubMed]
- Le TV, Smith DA, Greenberg MS, et al. Complications of lateral plating in the minimally invasive lateral transpsoas approach. J Neurosurg Spine 2012;16:302-7. [Crossref] [PubMed]
- Wu H, Cheung JPY, Zhang T, et al. The Role of Hounsfield Unit in Intraoperative Endplate Violation and Delayed Cage Subsidence with Oblique Lateral Interbody Fusion. Global Spine J 2021; Epub ahead of print. [Crossref] [PubMed]
- Woods KR, Billys JB, Hynes RA. Technical description of oblique lateral interbody fusion at L1-L5 (OLIF25) and at L5-S1 (OLIF51) and evaluation of complication and fusion rates. Spine J 2017;17:545-53. [Crossref] [PubMed]
